1. Field of the Invention
The present invention relates to an audio content file management method and apparatus, and in particular, to a method of a portable MP3 player that enables descriptive information of a MP3 audio file to be acquired and displayed quickly.
2. Background of the Related Art
A digital audio player can playback digitized audio data stored within the device in a standard format, such as MP3. MP3 digital audio data files are stored in nonvolatile memory, such as a flash-RAM memory card. In general, the files are organized on the storage device using a DOS-like logical memory allocation structure. An example of this organization is shown in FIG. 1 for the case of audio data stored on a memory card 30. As shown in FIG. 1, the allocation structure has a memory management information area and an audio data area. The memory management information area is partitioned into a boot sector, a file allocation table (FAT) containing information on data cluster locations and blank cluster locations, and a directory area. In a DOS system, one cluster is four 512-byte sectors. Therefore, a four MB MP3 file has about 2000 clusters, which may be written contiguously or dispersedly in the audio data file area.
The files are retrieved and reconstructed based on information written in the directory and the FAT. FIG. 2 shows a related art 32-byte-long directory entry composed of an 8-byte file name, 3-byte extension, 1-byte attribute, 10-byte reserved field, 2-byte creation time, 2-byte creation date, 2-byte start cluster location, and 4-byte file size. Beginning with the start cluster location stored in the directory, the files are reconstructed in the proper ordered sequence on a cluster-by-cluster basis, by referring to cluster location information stored in the FAT.
In addition to the audio data, MP3 files also contain descriptive information such as title of song and the artist's name. The descriptive information is used for displaying on a screen for the user. The descriptive information is appended to the last cluster of the file, following the string “TAG”.
As described above, the related art digital audio player and memory allocation structure have various disadvantages. If it is desired to retrieve and display the descriptive information of particular MP3 file, about 2000 clusters are traced sequentially from the start cluster location in the 2-byte start cluster directory entry for the file, to the last cluster containing the string “TAG” using the cluster location information stored in the FAT. The necessity for following the entire chain of linked clusters, in order to retrieve the descriptive information, results in an undesirable delay in the presentation of the information to the user.